Mechanical hard stops with moveable stop members

ABSTRACT

A mechanical hard stop for a sensor system includes a base for fixation to a gimbal or static structure, a movable stop member for engagement with a fixed stop member, and an actuator. The movable stop member has a disengaged position, proximate the base, and an engaged position, spaced apart from the base. The actuator is operably connected to the movable stop member to displace the movable stop member between the disengaged position and the engaged position according to a sensor selection received by the sensor system. Sensor systems and imaging methods are also described.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional of now granted U.S. patent applicationSer. No. 16/584,403 filed on Sep. 26, 2019, which claims the benefit ofpriority to U.S. Provisional Patent Application Ser. No. 62/736,947filed Sep. 26, 2018 the disclosures of each are herein incorporated byreference in their entirety.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present disclosure relates to sensor systems, and more particularlyto mechanical hard stops with movable stop members for limiting gimbalrotation in sensor systems.

2. Description of Related Art

Sensing systems, such as those employing cameras, are commonly used toimage scenes. During imaging the camera is generally oriented toward ascene to image the portion of the scene within the camera field of view.To increase the portion of a scene imaged cameras are typically fixed toa gimbal. The gimbal is generally rotatable with a finite rotationrange. Movement through the rotation range sweeps the camera's field ofview through the scene to define the camera's field of regard whileaccommodating constraints within sensor structure, such as cable runsbetween the camera and stationary structures in sensor system. Fixedstops are generally employed to prevent gimbal from rotating beyond therotation range, such as from shock and accelerations during flight thatotherwise could drive the gimbal beyond the rotation range.

One challenge with hard stops is that fixed mechanical hard stops cansometimes impose artificial constraints on the sensing system. Forexample, in sensing systems having more than one camera mounted to thegimbal with unequal fields of the view, the movement range defined bythe fixed mechanical stop can limit the field of regard to less thanwhat the camera(s) could otherwise provide. This unnecessarily limitsthe amount of information acquired during imaging.

Such conventional methods and systems have generally been consideredsatisfactory for their intended purpose. However, there is still a needin the art for improved mechanical hard stops for sensor systems, sensorsystems with mechanical hard stops, and imaging methods usingmechanically stopped sensor systems. The present disclosure provides asolution for this need.

SUMMARY OF THE INVENTION

A mechanical hard stop for a sensor system includes a base for fixationto a gimbal or static structure, a movable stop member for engagementwith a fixed stop member, and an actuator. The movable stop member has adisengaged position, proximate the base, and an engaged position, spacedapart from the base. The actuator is operably connected to the movablestop member to displace the movable stop member between the disengagedposition and the engaged position according to a sensor selectionreceived by the sensor system.

In certain embodiments the actuator can include a solenoid to displacethe movable stop member between the disengaged position and the engagedposition. A biasing member can be connected between the base and themovable stop member. The biasing member can bias the movable stop membertoward one of the disengaged position and the engaged position. Themechanical hard stop can conform in fit and form to a fixed stop memberfor a DB-100 sensor system.

In accordance with certain embodiments a controller can be connected tothe actuator. The controller can be responsive to instructions recordedon a memory to displace the movable stop member between the disengagedposition and the engaged position. The instructions can cause thecontroller to receive a sensor selection and displace the movable stopmember between the disengaged position and the engaged positionaccording to the received sensor selection. For example, theinstructions can cause the controller to displace the movable hard stopmember radially to the disengaged position when a narrow field of viewsensor carried by a gimbal is selected for imaging. It is alsocontemplated that the instructions can cause the controller to displacethe movable hard stop member radially to the engaged position when awide field of view sensor carried by a gimbal is selected for imaging.

A sensor system includes a gimbal and a mechanical hard stop asdescribed above. The gimbal is supported for rotation about an axisrelative to a static structure. The base of the mechanical hard stop isfixed relative to the static structure. The movable stop member limitsrotation of the gimbal when in the engaged position. The movable stopmember does not limit rotation of the gimbal in the disengaged position.

In certain embodiments cabling can connect a sensor carried by thegimbal to a controller fixed relative to the static structure. A fixedstop member can be carried by the gimbal. The fixed stop member can comein to circumferential abutment with the movable stop member when themovable stop member is in the engaged position. The mechanical hard stopcan be a first mechanical hard stop and the sensor system can include asecond mechanical hard stop as described above. The base of the secondmechanical hard stop can be fixed to the static structure. The secondmechanical hard stop can be offset from the first mechanical hard stopabout the axis by 45 degrees or less.

In accordance with certain embodiments the sensor system can include afaring with a window. The faring can envelope the sensor system. Thefaring can be fixed to the static structure. The window can be a firstwindow and the sensor system can include a second window. The secondwindow can be supported by the faring and offset from the first windowabout the axis. A sensor can be carried by the gimbal. The sensor canhave a field of view that is orthogonal relative to the axis. The sensorcan be a first sensor and the sensor system can have a second sensor.The second sensor can be carried by the gimbal and arranged on a side ofthe axis opposite the first sensor.

It is contemplated that, in accordance with certain embodiments, thesensor system can include a resolver. The resolver can be arranged todetermine rotational position of the gimbal about the axis. A drivemotor can be operably connected to the gimbal. The drive motor can beconfigured to rotate the gimbal about the axis. The axis can be a rollaxis. The axis can be a pitch axis. It is also contemplated that thesensor system can include first and second sensors carried by thegimbal, the first sensor having a field of view that is larger than afield of view of the second sensor, and a controller. The controller canbe operatively connected to the actuator and disposed in communicationwith a memory having instructions recorded on it that, when read by thecontroller, cause the controller to receive a sensor selection, displacethe movable stop member to the engaged position using the actuator whenthe first sensor is selected, and displace the movable stop member tothe disengaged position using the actuator when the second sensor isselected.

An imaging method includes, at a sensor system having mechanical hardstop as described above, receiving a sensor selection. When the firstsensor is selected the movable stop member is displaced radially to theengaged position using the actuator. When the second sensor is selectedthe movable stop member is displaced radially to the disengaged positionusing the actuator. In certain embodiments, a scene is imaged with thefirst sensor when the movable stop member is in the engaged position. Inaccordance with certain embodiments, a scene can be imaged with thesecond sensor when the movable stop member is in the disengagedposition.

These and other features of the systems and methods of the subjectdisclosure will become more readily apparent to those skilled in the artfrom the following detailed description of the preferred embodimentstaken in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

So that those skilled in the art to which the subject disclosureappertains will readily understand how to make and use the devices andmethods of the subject disclosure without undue experimentation,embodiments thereof will be described in detail herein below withreference to certain figures, wherein:

FIG. 1 is a side view of a sensor system, showing the sensor systemenveloped within a faring having a window for imaging a scene outsidethe faring through the window;

FIG. 2 is a side elevation view of the sensor system of FIG. 1,schematically showing first and second sensors carried by a gimbal ofthe sensor system;

FIG. 3 is an axial end view of the sensor system of FIG. 1,schematically showing mechanical hard stops with movable stop membersand a fixed stop member to define different rotation movement ranges ofthe gimbal;

FIG. 4 is a side view of the movable stop member and a fixed stop memberof the sensor system of FIG. 1, showing a controller operativelyconnected to the mechanical hard stop and disengaged and engagedpositions of the mechanical hard stop movable stop member;

FIGS. 5-7,11 and 12 are axial end views of the sensor system of FIG. 1,showing a rotational movement range and field of regard of a firstsensor when movable stop members of a mechanical hard stops are in theengaged and disengaged positions, respectively;

FIGS. 9-10, 13 and 14 are axial end views of the sensor system of FIG.1, showing a rotational movement range and field of regard of a secondsensor when movable stop members of a mechanical hard stops are in thedisengaged and engaged positions, respectively; and

FIG. 15 is a block diagram of an imaging method, showing steps of theimaging method according to an exemplary embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference will now be made to the drawings wherein like referencenumerals identify similar structural features or aspects of the subjectdisclosure. For purposes of explanation and illustration, and notlimitation, a sensor system with a mechanical hard stop having a movablestop member is shown in FIG. 1 and is designated generally by referencecharacter 102. Other embodiments of mechanical hard stops, sensorsystems having mechanical hard stops with movable stop members, andimaging methods are shown in FIGS. 2-15, as will be described. Thesystems and methods described herein can be used in intelligencesurveillance and reconnaissance (ISR) sensor systems, such as in sensorsystems having more than one sensor mounted on a common gimbal, thoughthe present disclosure is not limited to sensor systems having more thanone sensor or to ISR systems in general.

Referring to FIG. 1, sensor system 102 is shown. Sensor system 102 isenveloped within the interior of a faring 104. Faring 104 includes awindow 106 which provides a viewing area for data collection from ascene 10 located outside of faring 104. In the illustrated exemplaryembodiment window 106 is a first window and faring 104 includes at leastone second window, e.g., a second window 108 (shown in FIG. 11) and athird window 110. It is contemplated that sensor system 102 be arrangedas an ISR sensor system, such as an ISR system carried by an aircraft12. Examples of suitable ISR sensor systems include dual-band ISR sensorsystems, such as DB-110 sensor systems, available United TechnologiesAerospace Systems of Charlotte, N.C. In certain embodiments mechanicalhard stop 100 conforms in fit and form to a fixed stop member for aDB-110 sensor system, facilitating integration of mechanical hard stop100 into DB-110 sensor systems.

With reference to FIG. 2, sensor system 102 is shown. Sensor system 102includes a static structure 112, a roll gimbal 114, and pitch gimbal116. Faring 104 is fixed relative to static structure 112 and issupported thereby. Roll gimbal 114 is connected to static structure 112and is supported thereby for rotation about a roll axis 118. Rotation ofroll gimbal 114 about roll axis 118 is effected by a roll resolver/drivearrangement 120, which is operably connected to roll gimbal 114 forrotating, roll gimbal 114 about roll axis 118. As shown in FIG. 2 acontroller 122 is disposed in communication with roll resolver/drivearrangement 120 through cabling 124, through which controller 122controls rotation of roll gimbal 114 about roll axis 118.

Pitch gimbal 116 is connected to roll gimbal 114 and is supportedthereby for rotation about a pitch axis 126. Rotation of pitch gimbal116 about pitch axis 126 is effected by a pitch resolver/drivearrangement 128, which is operably connected to pitch gimbal 116 forrotating pitch gimbal 116 about pitch axis 126 and which is itselfcarried by roll gimbal 114. As also shown in FIG. 2 controller 122 isdisposed in communication with pitch resolver/drive arrangement 126through cabling 124, through which controller 122 also controls rotationof pitch gimbal 116 about pitch axis 126.

Pitch gimbal 116, and therethrough roll gimbal 114, carry a first sensor130 and a second sensor 132. Second sensor 132 is arranged on a side ofroll axis 118 opposite first sensor 130, either (or both) first sensor130 and second sensor 132 being disposed in communication withcontroller 122 for receiving data from either (or both) first sensor 130and second sensor 132. Data from first sensor 130 and second sensor 132is provided through cabling 124, which provides connectivity for digitaldata communication between the sensors and controller 122.

Controller 122 is fixed relative to static structure 112. Since cabling124 runs between movable structures, e.g., pitch resolver/drivearrangement 128, first sensor 130, and second sensor 132, it isnecessary to limit the movement of one or more of the movable structuresrelative to static structure 112. This prevents damage on cabling 124that could otherwise occur from rotation of roll gimbal 114. Limitationof movement of roll gimbal 114 is effected by mechanical hard stop 100.As will be appreciated by those of skill in the art in view of thepresent disclosure, the disadvantages otherwise associated with havingto manage cabling 124 can be offset by the advantages provided by thequality of the data communication connection provided by cabling 124,which allows first sensor 130 and second sensor 132 to communicate imagedata with the data loss that could otherwise accompany the use of a slipring or other type of data communication interface.

In the illustrated exemplary embodiment and as described hereinmechanical hard stop 100 is a first mechanical hard stop 100 a andlimitation of movement of roll gimbal 114 is effected by cooperation offirst mechanical hard stop 100 a with one or more of a second mechanicalhard stop 100 b and a fixed stop member 136. Although a particularmechanical hard stop arrangement is shown, e.g., mechanical hard stopswith moveable stop members connected to static structure and a fixedstop member connected to a gimbal, it is to be understood andappreciated that other arrangements are possible within the scope of thepresent disclosure. For example, mechanical hard stops with movable stopmembers can be carried by the gimbal and a fixed stop member attached tothe static structure. Further, pitch gimbal 14 can also be stopped usinga mechanical stop with movable stop/fixed stop member arrangement, assuitable for an intended application.

With reference to FIG. 3, sensor system 102 is shown in an axial endview. As shown in FIG. 3 roll gimbal 114 extends about roll axis 118 andcarries first sensor 130 and second sensor 132. Static structure 112extends about roll gimbal 114 and is located radially outward of rollgimbal 114. Second sensor 132 is arranged on a side of roll axis 118opposite first sensor 130 and has a second sensor field of 172. Secondsensor field of view 172 is smaller than a field of view 162 of firstsensor 130. In certain embodiments first sensor 130 can be a wide fieldof view sensor, such as optical waveband sensor. Examples of opticalwaveband sensors include cameras and telescopes. In accordance withcertain embodiments second sensor 132 can be a narrow field of viewsensor, such as an infrared waveband sensor. Examples of infraredsensors include infrared sub-waveband imaging arrays.

Fixed stop member 136 is carried by roll gimbal 114. In this respectfixed stop member 136 is fixed relative to roll gimbal 114 and islocated at singular radial position from roll axis 118 irrespective ofwhich sensor carried by roll gimbal 114 is used for imaging. As will beappreciated by those of skill in the art in view of the presentdisclosure, fixation in to rob gimbal 114 allows fixed stop member 116to come into circumferential abutment with first movable stop member 138a when in engaged position 142 a or second movable stop member 138 bwhen in engaged position 142 b, thereby preventing further rotation ofroll gimbal 114.

First mechanical hard stop 100 a and second mechanical hard stop 100 bare each fixed relative to static structure 112. This means that bothfirst mechanical hard stop 100 a and second mechanical hard stop 100 bare arranged at fixed circumferential positions relative to one anotherand in relation to fixed stop member 136, which is carried by rollgimbal 114 and movable relative to first mechanical hard stop 100 a andsecond mechanical hard stop 100 b. In the illustrated exemplaryembodiment second mechanical hard stop 100 b is circumferentially offsetfrom first mechanical hard stop 100 a by an angular offset that is lessthan about 45 degrees. Angular offsets of about 45 degrees allows forcooperation of first mechanical hard stop 100 a and second mechanicalhard stop 100 b such that the field of view of each first sensor 130 andsecond sensor 132 can be swept across the entirety of both first window106 (shown in FIG. 1) and second window 108 (shown in FIG. 4), datacollection thereby being limited by the boundaries defined by firstwindow 130 and second window 132 and not engagement of one fixed stopmember with another fixed stop member.

Instead, first mechanical hard stop 100 a has a movable stop member 138a. Movable stop member 138 a is movable radially, e.g., toward and awayfrom roll axis 118, between an engaged position 142 a (shown in dashedoutline) and a disengaged position 140 a (shown in solid outline). Inthe disengaged position 140 a movable stop member 138 a does not impedethe rotation of roll gimbal 114 as fixed stop member 136 passes. As willbe appreciated by those of skill in the art in view of the presentdisclosure, this allows roll gimbal 114 to rotate past first mechanicalhard stop 100 a without limitation by first mechanical hard stop 100 a.In contrast, when in the engaged position 142 a, movable stop member 138a moves radially inward toward roll gimbal 114 such that fixed stopmember 136 cannot rotate past first mechanical hard stop 100 a, firstmechanical hard stop 100 a thereby limiting rotation of roll gimbal 114.Second mechanical hard stop 100 b is similar to first mechanical hardstop 100 a with the difference that second mechanical hard stop 100 b isrotationally offset from first mechanical hard stop 100 a about rollaxis 118. As will be appreciated by those of skill in the art in view ofthe present disclosure, this allows second mechanical hard stop 100 b tolimit rotation of roll gimbal 114 to a within a different rotationalrange than first mechanical hard stop 100 a according to the position ofa second movable stop member 138 b of second mechanical hard stop 100 b.

With reference to FIG. 4, first mechanical hard stop 100 a is shown.First mechanical hard stop 100 a includes a base 144 a for fixation toroll gimbal 114 or static structure 112, movable stop member 138 a forengagement with fixed stop member 136, and an actuator 146 a. Moveablestop member 138 a has disengaged position 140 a, which is proximate tobase 144 a, and engaged position 142 a, which is spaced apart from base144 a. Actuator 146 a is operably connected to movable stop member 138 ato displace movable stop member 138 a between disengaged position 140 aand engaged position 142 a according to a sensor selection 16 receivedby sensor system 102 (shown in FIG. 1).

First mechanical hard stop 100 a includes a biasing member 148 a.Biasing member 148 a is arranged between base 144 a and movable stopmember 138 a and is arranged to bias movable stop member 138 a towardone of engaged position 142 a and disengaged position 140 a. As shown inFIG. 4, actuator 146 a, includes a solenoid 150 a to effect movement ofmovable stop member 138 a between engaged position 142 a and disengagedposition 140 a. As will be appreciated by those of skill in the art inview of the present disclosure, actuator 146 a can alternatively includeother types of motive devices to effect movement of movable stop member138 a between engaged position 142 a and disengaged position 140 a, suchas electric motors with and without gearing, pneumatics, and/orhydraulics, and remain within the scope of the present disclosure.

As also shown in FIG. 4, controller 122 is connected to first mechanicalhard stop 100 a. Controller 122 includes a processor 150, a userinterface 152, and a cabling interface 154. Cabling interface 154 isdisposed in communication with actuator 146 a through cabling 124, whichconnects controller 122 to actuator 146 a, and is additionally disposedin communication with processor 152. Processor 152 is in turncommunicative with user interface 152 and a memory 156 having aplurality of program modules 158 recorded thereon with instructionsthat, when ready by processor 152, cause processor to execute certainoperations.

For example, responsive to the instructions recorded on memory 156,controller 122 can displace movable stop member 138 a between disengagedposition 140 a and engaged position 142 a. Further, instructions cancause controller 122 to receive sensor selection 16 and, based on thesensor identified with sensor selection 16, displace movable stop member138 a between disengaged position 140 a and engaged position 142 aaccording to received sensor selection 16. In certain embodiments theinstructions cause controller 122 to displace movable stop member 138 ato disengaged position 140 a when second sensor 132 carried by rollgimbal 114 is selected for imaging. In accordance with certainembodiments, the instructions can cause controller 122 to displacemovable stop member 138 a to engaged position 142 a when first sensor130 carried by roll gimbal 114 is selected for imaging. It iscontemplated that the displacement of movable stop member 138 a beincorporated in an imaging method, e.g., an imaging method 200 (shown inFIG. 15), as will be described. Second mechanical hard stop 100 b issimilar to first mechanical hard stop 100 a and is additionally locatedon static structure 112 at a location rotationally offset from firstmechanical hard stop 100 a.

With reference to FIGS. 5-9, a rotational ranges of first sensor 130 isshown. When first sensor 130 is selected for imaging it is contemplatedthat controller 122 configure first mechanical hard stop 100 a andsecond mechanical hard stop 100 b such that the field of regard of firstsensor 130 is limited by the edges of first window 106 (shown in FIG. 8)and second window 108 (shown in FIG. 9) rather than the location offixed stop member 136 in sensor system 102. Controller 122 thereforeactuates second mechanical stop 100 b such that second movable stopmember 138 b (shown in FIG. 4) displaces to disengaged position 140 b(shown in FIG. 4). Controller 122 also actuates first mechanical hardstop 100 a such that movable stop member 138 a (shown in FIG. 4)displaces to engaged position 142 a (shown in FIG. 4). This causes firstmechanical hard stop 100 a to determine the rotational limits of rollgimbal 114 about roll axis 118.

Movement of second movable stop member 138 b to disengaged position 140b allows roll resolver/drive arrangement 120 to rotate roll gimbal 114about roll axis 118 such that fixed stop member 136 is able to rotatepast second movable stop member 138 b, the rotary movement of rollgimbal 114 continuing until fixed stop member 136 comes into abutmentwith first movable stop member 138 a. Once fixed stop member 136 comesinto abutment with first movable stop member 138 a rotation of rollgimbal 114 ceases. As shown in FIGS. 6 and 7, relative to the port sidehorizon during level flight of aircraft 10 (shown in FIG. 1), thepositioning of first movable stop member 138 a and second movable stopmember 138 b shown in FIG. 5 allow roll gimbal 114 to rotate clockwisein a rotary movement 180 of about 210 degrees, as shown in FIG. 6, andcounterclockwise in a rotary movement 182 of about 150 degrees, as shownin FIG. 7. As shown in FIGS. 8 and 9, this allows the field of view offirst sensor 130 to completely overlap both first window 106 and secondwindow 108, the field of regard of first sensor 130 thereby limited bythe uppermost (relative to the top of FIG. 9) edges of first window 106and second window 108.

Referring to FIGS. 10-14, a rotational range 150 b of second sensor 132is shown. When second sensor 132 is selected for imaging it iscontemplated that controller 122 configure first mechanical hard stop100 a and second mechanical hard stop 100 b such that the field ofregard of second sensor 132 is also limited by the edges of first window106 (shown in FIG. 8) and second window 108 (shown in FIG. 9) ratherthan the location of fixed stop member 136. Controller 122 thereforeactuates second mechanical hard stop 100 b such that second movable stopmember 138 b moves to engaged position 142 b and first mechanical hardstop 100 a such that first movable stop member 138 a moves to disengagedposition 140 a. This causes second mechanical hard stop 100 b todetermine the rotational limits of roll gimbal 114 about roll axis 118.

Movement of first movable stop member 138 a to disengaged position 140 aallows roll resolver/drive arrangement 120 to rotate roll gimbal 114about roll axis 118 such that fixed stop member 136 is able to rotatepast first movable stop member 138 a, rotary movement of roll gimbal 114continuing until fixed stop member 136 comes into abutment with secondmovable stop member 138 b. Once fixed stop member 136 comes intoabutment with second movable stop member 138 b rotation of roll gimbal114 ceases. As shown in FIGS. 11 and 12, relative to the port sidehorizon during level flight of aircraft 10, the positioning of firstmovable stop member 138 a and second movable stop member 138 b shown inFIG. 10 allow roll gimbal 114 to rotate clockwise in a rotary movementof about 150 degrees, as shown in FIG. 11, and counterclockwise in arotary movement of about 275 degrees, as shown in FIG. 12. As shown inFIGS. 13 and 14, this allows the field of view of second sensor 132 tocompletely overlap both first window 106 and second window 108, thefield of regard of second sensor 132 maximized as limited by the edgesof first window 106 and second window 108. Notably, first sensormovement 190 (shown in FIG. 12) and second sensor movement 192 (shown inFIG. 14) each start and terminate at different rotational positionsaccording to the positions of first movable stop member 138 a and secondmovable stop member 138 b.

With reference to FIG. 15, an imaging method 200 is shown. Imagingmethod 200 includes receiving a sensor selection, e.g., sensor selection16 (shown in FIG. 3), as shown with box 210. When a first sensor isselected, e.g., first sensor 130 (shown in FIG. 2), a movable stopmember is moved to the engaged position, as shown by boxes 220 and 230.A scene, e.g., scene 12 (shown in FIG. 1), is then imaged using thefirst sensor by rotating the first sensor to define a first sensor fieldof regards hounded by windows of the imaging system, e.g., first window106 (shown in FIG. 3) and second window 108 (shown in FIG. 3), as shownwith box 240. In this respect a first movable stop member, e,g., firstmovable stop member 138 a (shown in FIG. 3), is moved to the engagedposition, as shown with box 232. It is contemplated that a secondmovable stop member, e.g., second movable stop member 138 b (shown inFIG. 13), can be moved to the disengaged position, e.g., disengagedposition 140 b (shown in FIG. 13), as shown with box 234.

When a second sensor is selected, second sensor 132 (shown in FIG. 2),the movable stop member can be displaced to the disengaged position,e.g., disengaged position 140 a (shown in FIG. 3), as shown with box 250and box 260. The scene is then imaged using the second sensor byrotating the second sensor to define a second sensor field of regardsbounded by windows, as shown with box 270. When the second sensor isselected it is contemplated that the first movable sensor be moved tothe disengaged position, e.g., disengaged position 140 a (shown in FIG.3), and that the second movable stop member be moved to an engagedposition, e.g., engaged position 142 b (shown in FIG. 14). as shown withbox 262 and box 264.

The methods and systems of the present disclosure, as described aboveand shown in the drawings, provide for sensor systems with superiorproperties including the capability to adjust the rotational movementrange of a gimbal. In certain embodiments the capability to adjust themovement range allows changing the rotational movement range of thegimbal according to a sensor selection, allowing the field of regard ofthe selected sensor to be limited by the sensor window instead by afixed stop member, expanding the field of regard of the sensor. Whilethe apparatus and methods of the subject disclosure have been shown anddescribed with reference to preferred embodiments, those skilled in theart will readily appreciate that changes and/or modifications may bemade thereto without departing from the scope of the subject disclosure.

What is claimed is:
 1. A mechanical hard stop for a sensor system,comprising: a base configured for fixation to a gimbal or staticstructure; a movable stop member configured for engagement with a fixedstop member, the movable stop member having a disengaged position,proximate the base, and an engaged position, spaced apart from the base;and an actuator operably connected to the movable stop member andconfigured to displace the movable stop member between the disengagedposition and the engaged position according to a sensor selectionreceived by the sensor system.
 2. The mechanical hard stop as recited inclaim 1, wherein the actuator includes a solenoid to displace themovable stop member between the disengaged position and the engagedposition.
 3. The mechanical hard stop as recited in claim 1, furthercomprising a biasing member connected between the base and the movablestop member, the biasing member biasing the movable stop member towardone of the disengaged position and the engaged position.
 4. Themechanical hard stop as recited in claim 1, wherein the mechanical hardstop conforms in fit and form to a fixed stop member for a DB-100 sensorsystem.
 5. The mechanical hard stop as recited in claim 1, furthercomprising a controller connected to the actuator and responsive toinstructions recorded on a memory to displace the movable stop memberbetween the disengaged position and the engaged position.
 6. Themechanical hard stop as recited in claim 5, wherein the instructionsrecorded on the memory further cause the controller to: receive a sensorselection; and displace the movable stop member between the disengagedposition and the engaged position according to the received sensorselection.
 7. The mechanical hard stop as recited in claim 5, whereinthe instructions recorded on the memory cause the controller to displacethe movable stop member radially to the disengaged position when anarrow field of view sensor carried by a gimbal is selected for imaging.8. The mechanical hard stop as recited in claim 5, wherein theinstructions recorded on the memory cause the controller to displace themovable stop member radially to the engaged position when a wide fieldof view sensor carried by a gimbal is selected for imaging.
 9. A sensorsystem, comprising: a gimbal supported for rotation about an axisrelative to a static structure; a mechanical hard stop as recited inclaim 1, wherein the base of the hard stop is fixed to the staticstructure, wherein the movable stop member limits rotation of the gimbalin the engaged position, wherein the movable stop member does not limitrotation of the gimbal in the disengaged position.
 10. The sensor systemas recited in claim 9, further comprising a fixed stop member carried bythe gimbal and circumferentially overlapped by the movable stop member.11. The sensor system as recited in claim 9, wherein the mechanical hardstop is a first mechanical hard stop and further including a secondmechanical hard stop as recited in claim 1, wherein the base of thesecond mechanical is connected to the static structure.
 12. The sensorsystem as recited in claim 11, wherein the second mechanical hard stopis offset from the first mechanical hard stop about the axis by 45degrees or less.
 13. The sensor system as recited in claim 9, furthercomprising a faring with a window enveloping the sensor system, thefaring fixed to the static structure.
 14. The sensor system as recitedin claim 13, wherein the window is a first window and further comprisinga second window, the second window supported by the faring and offsetfrom the first window about the axis.
 15. The sensor system as recitedin claim 9, further comprising a sensor carried by the gimbal, wherein afield of view of the sensor is orthogonal relative to the axis.
 16. Thesensor system as recited in claim 15, wherein the sensor is first sensorand further comprising a second sensor, wherein the second sensor iscarried by the gimbal, Wherein the second sensor is arranged on a sideof the axis opposite the first sensor.
 17. The sensor system as recitedin claim 9, further comprising cabling connecting a sensor carried bythe gimbal and a controller fixed relative to the static structure. 18.The sensor system as recited in claim
 9. further comprising aresolver/drive arrangement operably connected to the gimbal andconfigured to rotate the gimbal about the axis.
 19. The sensor system asrecited in claim 9, further comprising: first and second sensors carriedby the gimbal, the first sensor having a field of view that is largerthan a field of view of the second sensor; and a controller operativelyconnected to the actuator and disposed in communication with a memoryhaving instructions recorded on it that cause the controller to: receivea sensor selection; displace the movable stop member to the engagedposition using the actuator when the first sensor is selected; anddisplace the movable stop member to the disengaged position using theactuator when the second sensor is selected.
 20. An imaging methodcomprising: at a sensor system including mechanical hard stop with abase, a movable stop member having a disengaged position proximate thebase and an engaged position spaced apart from the base, and an actuatoroperably connected to the movable stop member, receiving a sensorselection; displacing the movable stop member to the engaged positionusing the actuator when the first sensor is selected; and displacing themovable stop member to the disengaged position using the actuator whenthe second sensor is selected.